introduction to cells

Question 1

3 facts about the cell theory

Answer 1

1. All living things are composed of cells
2. the cell is the smallest unit of life
3. cells only arise from pre-existing cells

Question 2

exceptions to cell theory

Answer 2

1. Skeletal muscle - much larger fibres (like cells) then normal
2. Giant Algae - contain only single nucleus so not multicellular
3. aseptate fungi - long undivided sections of hypha which contain many nuclei

Question 3

what are unicellular organisms?

Answer 3

Unicellular organisms consist of only one cell and carry out all functions of life in that cell

Question 4

7 basic functions integral to survival

Answer 4

1. Metabolism - chemical reactions undertaken
2. Reproduction - produce offspring (sexually or asexually)
3. Sensitivity - responsive to internal and external stimuli
4. Homeostatis - maintaining a stable internal environment
5. Excretion - removal of waste products
6. Nutrition - exchange materials and gases with environment
7. Growth - move and changing shape or size

Question 5

2 examples of unicellular organisms:

Answer 5

1. Paramecium
2. Chlamydomonas

Question 6

paramecium 7 basic functions

Answer 6

Mr Sheng
1. produces enzymes which catalyse many different chemical reactions in the cytoplasm
2. reproduce asexually using mitosis or sexually using meiosis and gametes
3. reacts to stimuli
4. keep internal conditions within limits
5. expels waste products of metabolism
6. feed on smaller organisms by ingesting and digesting through vescicles
7. increase in size and mass by accumulating organic matter and minerals from its food

Question 7

Chlamydomonas 7 basic functions

Answer 7

Mr Sheng
1.produces enzymes which catalyse many different chemical reactions in the cytoplasm
2.reproduce asexually using mitosis or sexually using meiosis and gametes
3. reacts to stimuli
4. keep internal conditions within limits
5. expels waste products of metabolism
6. Produces its own food by photosynthesis using a chloroplast that occupies much of the cell
7. increase in size and mass due to photosynthesis and absorption of minerals

Question 8

production of chemical energy by cells

Answer 8

cells need to produce chemical energy (via metabolism) to survive and this requires the exchange of materials with the environment

Question 9

multicellular organisms

Answer 9

Large organisms are multicellular since they consist of many cells

Question 10

advantages of multicellular organisms

Answer 10

1. division of labour (different groups of cells/tissues become specialized for different functions by the process of differentiation)

Question 11

metabolism

Answer 11

function of its mass / volume

Question 12

rate of material exchange

Answer 12

function if its surface area

Question 13

surface area to volume ratio

Answer 13

surface area ÷ by volume

Question 14

calculation of magnification

Answer 14

magnification = Image size ÷ Actual size

Question 15

light microscope

Answer 15

light microscopes use visible light and a combination of lenses to magnify images of mounted specimens

Question 16

what are emergent properties

Answer 16

emergent properties arise when the interaction of individual component produce new functions

Question 17

multicellular organism functions

Answer 17

1. Cells may be grouped together to form tissues
2. Organs are then formed from the functional grouping of multiple tissues
3. Organs that interact may form organ systems capable of carrying out specific body functions
4. Organ systems collectively carry out the life functions of the complete organism

Question 18

organisation of Mulicellular organisms

Answer 18

from: Muscle (cell) -> Cardia (Tissue) -> Heart (organ) -> Vascular (system) -> Human (organism)

Question 19

differentiation

Answer 19

process during development whereby newly formed cells become more specialized and distinct from one another as they mature

Question 20

how is chromatin formed?

Answer 20

Within the nucleus of a eukaryotic cell, DNA is packaged with proteins to form chromatin.

Question 21

gene packaging

Answer 21

1. active genes are packed in an euchromatin
2. inactive genes have different regions of DNA packaged as euchromatin and heterochromatin

Question 22

stem cells qualities:

Answer 22

1. self renewal - continuously divide and replicate
2. Potency - capacity to differentiate into specialised cell types

Question 23

types of stem cells

Answer 23

1. Totipotent - can form any cell type as well as extra embryonic tissue
2. Pluripotent - can form any cell type
3. Multipotent - can differentiate into a number of closely related cell types
4. Unipotent - can not differentiate, but can self renew

Question 24

what are stems cells necessary for?

Answer 24

stem cells are necessary for embryonic development as they are an undifferentiated cell source from which all other cell types may be derived

Question 25

what can stem cells be used for ?

Answer 25

to replace damaged or diseased cells with healthy, functioning ones. the process requires; biochemical solutions, surgical implantation, suppression of host immune system, careful monitoring

Question 26

examples of stem cell therapy

Answer 26

1. Statgardts Disease - caused by gene mutation and causes vision loss (progressive)
2. Parkinsons Disease - degenartive disorder caused by the death of dopamine secreting cells in the midbrain

Question 27

stem cells Therapeutic examples

Answer 27

1. Leukemia
2. Paraplegia
3. Diabetes
4. Burn victims

Question 28

three sources that derive stem cells:

Answer 28

1. Embryos
2. Umbilical cord
3. adult tissues (ex. bone marrow)

Question 29

ethical considerations

Answer 29

1. multipoint adult tissue can be limited in its application
2. stem cells derived from umbilical cords blood need to be stored and preserved at high cost
3. pluripotent stem cells need the destruction of potential living organisms

Question 30

artificial stem cells techniques

Answer 30

1. Somatic cell nuclear transfer (creation of embryonic clones)
2. Nuclear reprogramming ( induce a change in the gene expression profile)